1. Field of the Invention
The present invention relates to a semiconductor device and a method of fabricating the same.
2. Description of the Related Art
To increase the driving current of a transistor in a semiconductor device, it is desirable to use a material having high stress as an insulating film covering source/drain regions and gate electrodes, and deposit this insulating film as a thicker layer.
If a narrow spacing between the gate electrodes is closed by increasing the thickness of this insulating film, however, it becomes difficult to maintain films formed as sidewall spacers of the gate electrodes, since the thickness of the gate electrode film is added to an effective film thickness to be removed when forming different insulating films in nMOS and pMOS transistors. In addition, if films formed as stoppers of the sidewall spacer films are also removed, etching damage enters source/drain extension regions as well, and this degrades the junction leakage characteristic.
If a thin film that does not close the narrow spacing between the gate electrodes is formed as the insulating film in order to avoid the above problem, insufficient stress is applied to the channel portion of the transistor, so the desired driving current cannot be obtained.
Note that Jpn. Pat. Appln. KOKAI Publication No. 2003-273240 describes steps of forming insulating films having different stresses in an nMOSFET and pMOSFET.